Following pretreatment, woody biomass can be converted into simple sugars by enzymatic deconstruction via a cellulase treatment. This remains the second most expensive component in the bioconversion of wood to bioethanol, despite the fact that research studies over the past decade have decreased cellulase costs by greater than a 10-fold basis. Numerous publications and reviews have highlighted the use of (i) separate hydrolysis and fermentation (SHF) and

(ii) simultaneous saccharification and fermentation (SSF) to convert pretreated wood to ethanol (Wingren et al., 2003; Wyman, 1994). A process challenge in the conversion of wood to biofuels is the efficient conversion of all wood sugars (i. e., C5 and C6) to ethanol, especially for hardwoods which have greater amounts of pentoses.

One promising strategy has been to take a natural hexose ethanologen and add the pathways to convert other sugars (Helle et al., 2004; Lawford and Rousseau, 2002). An alter­native approach to minimize the cost of cellulose deconstruction and conversion to ethanol is consolidated bioprocessing (CBP). CBP involves (i) bioproduction of cellulolytic enzymes from thermophilic anaerobic microbes, (ii) hydrolysis of plant polysaccharides to simple sugars and (iii) their subsequent fermentation to ethanol all in one stage (Lynd et al.,

2005) . This bioprocess is projected to reduce the cost of bioethanol by a factor of four over SSF, and these reduced costs and simplicity of operation have heightened research in this field.